Stop-motion devices relating to sewing machine bobbins



May 22, 1956 E. VOSSEN 2,747,039

STOP-MOTION DEVICES RELATING TO SEWING MACHINE BOBBINS Filed June 1, 1953 ay. 1. Jug. 2.

INVENTOR [OW/W0 1 0555 BY E W ATTORN EY United States Patent STOP-MOTION DEVICES RELATING TO SEWlN G MACHINE ROBBINS Edward Vossen, Lynbrook, N. Y., assignor to Stop-Motion Devices Corp., Brooklyn, N. Y.

Application June 1, 1953, Serial No. 358,822

2 Claims. (Cl. Mill-41.18)

This invention relates to stop-motion devices relating to sewing machine bobbins.

The principal object of this invention is to provide a stop-motion switch of the character described which is made of extremely few, simple component parts for fast and fool-proof operation. The basic form or" this invention comprises but three component parts: a bracket, a biased contact member which includes an insulated catch, and a pivotally mounted member which has a probe portion at one end and a contact member at its opposite end. The probe portion is engageable with the needle thread when the bobbin thread either breaks or terminates, as will hereinafter more fully be described, and its contact end is engageable in the first instance with the insulated catch and, in the second instance, upon breaking or termination of the bobbin thread and consequent actuation of the probe end, it is en gageable with the insulated portion of said biased contact member. Actually, therefore, there is only one movable part, namely, the pivotally mounted member which has a probe portion at one end and a contact member at its opposite end. The bracket is, of course, fixed to the sewing machine and although it may be removed for any desired purpose, it is nonetheless normally a stationary fixture on the machine. The biased contact member with the insulated catch is also a sta tionary member although it does flex either into or out of engagement with the contact end of the pivotally mounted er. if desired, a casing may be secured to the bracket or it may be made a part of the bracket so as to enclose the biased contact member with its in sulated catch and the contact end of the pivotally mounted member. The only exposed part of the device, therefore, would be the probe end of the pivotally mounted member.

This stop-motion device is intended primarily for use in connection with industrial sewing machines but it may, or course, also be applied to domestic sewing machines. it is particularly useful in connection with long production runs of continuous or joined lengths of work. The installation of this device renders it possible for a single sewing machine operator to manage the operation of a plurality of sewing machines running concurrently. For example, this device enables a single operator to tend as many as four, five and even six or more sewing machines simultaneously.

The use of the present device presupposes the use of a special kind of sewing machine presser foot or of a conventional presser foot modified in the manner indicated in the drawing and specification. Conventional sewing machines of the general character indicated are provided with a presser foot having a relatively small opening for the needle and the needle thread. This small opening tends to confine the needle thread to a substantially vertical position when the needle is in elevated position, both when the bobbin thread is engaged and when the bobbin thread is disengaged, as in the case of a break in the bobbin thread or when the bobbin is spent.

The presser foot which this invention requires is provided with an elongated hole for the needle and the needle thread, said needle hole being elongated particularly in rearward direction, that is, in the direction of the presser foot shank. in addition to such elon ated hole, an inclined groove or channel is provided in the heel of the presser foot, extending upwardly and forwardly into communication with said elongated hole. When the bobbin thread is disengaged, either by reason of a break or by reason of its termination, the needle thread will tend to assume an angular position through said inclined channel and said elongated hole when the needle moves to its elevated position. The probe of the stopmotion switch projects into the space between the S1 ank of the presser foot and the needle, immediately above the presser foot. When the bobbin thread breaks or terminates, the needle thread will assume its angular position above mentioned and it will thereby engage the probe. The pivotally mounted member of the switch is normally situated with its contact end in engagement with the insulated catch of the contact member. When the probe is engaged by the angularly po sitioned needle thread, the pivotally mounted member is caused to pivot and to unseat its contact end from the insulated catch. its contact end thereupon engages the contact member and the circuit to the stop-motion mechanism is thereby closed. The stop-motion mechanism goes into operation and the machine is stopped.

To re-set or cock the stop-motion switch herein described and claimed, all that need be done is manually to pivot the pivotally mounted member in the opposite direction from that last above mentioned. The contact end of said pivotally mounted member is thereby returned to the insulated seat and the probe end assumes its original position awaiting engagement by the needle thread wh n the bobbin thread breaks or terminates.

in a modified form of this invention, a separate and independent re-setting or cocking mechanism is provided. This mechanism also includes a movable contact member which engages the fixed contact member when in one position and disengages said fixed contact member when moved into another position. This form of the invention, like the first form above mentioned, includes a pivotally mounted member having a probe at one end. But While in the first form the opposite end of the pivoted member serves as a contact member, the opposite end of the pivoted member in the second form serves simply as a trip or catch or trigger with respect to the movable contact member of the resetting mechanism.

Preferred forms of this invention are accompanying drawing in which:

Fig. l is a side view of a switch made in accordance with the first form of this invention.

Fig. 2 is a side view of a switch made in accordance with the second form of this invention.

Fig. 3 is a perspective view of the switch shown in Fig. 1.

Sewing machine it) is a conventional machine, of the type used in industry for long continuous production runs. A presser foot 12 mounted at the end of a shank 14 is provided in the machine in conventional manner. Needle 16 is also conventiona and it passes through an elongated opening 18 in the presser foot as Fig. 1 clearly shows. An inclined groove 2% is formed in said presser foot, starting at the heel and extending forwardly upwardly in communication with said opening 13. As has above been indicated, when the bobbin thread breaks or terminates, the needle thread 22 is enabled to assume its angular position shown in Fig. l ince it is enabled to move backwardly through elongated opening 18 and groove 20 shown in the with the work. It is when this angular portion of the needle thread engages the probe of the stop-motion switch herein claimed that the switch closes and the stop-motion mechanism (not shown) goes into operation to stop the machine.

As has above been indicated, stopmotion switch made in accordance with the basic form of this invention comprises the following component parts: a substantially L-shaped bracket 32, a contact member 34, and a pivotally mounted arm 35. The bracket is of such size and shape that it may be secured to the back of the head or" the machine as the drawing clearly shows. The vertical portion of said L-shaped bracket may be bent and offset in the manner shown or it may be made perfectly straight or shaped in any other manner to adapt it to the individual requirements of each individual type of sewing machine to which the stop-motion switch herein claimed is to be applied. Similarly, although the bracket is shown secured to the back of the head of the machine, it may equally as readily be secured to the base of the machine.

A casing or cover 33 may be secured to the bracket in the manner shown in order to enclose and protect the working parts of the switch. For purposes of clarity the casing is almost completely broken away in the drawing to expose the working parts of the switch. It will be understood that the casing may be a separate entity secured by screws or other fastening means to the bracket or it may be made integrally with the bracket as, for example, by die-casting means and methods.

A'tfixed to the vertical portion 32a of bracket 32 is contact member 3d. This contact member is simply a leaf spring which is biased forwardly, that is, rightwardly as viewed in Fig. 1. It is secured at its upper end to said vertical portion of the bracket by means of a bolt 42 which also serves as a binding post or terminal for one of the wires of the circuit (not shown). In one form of this invention, both the contact member 34 and the bolt 42 are insulated from their supporting bracket 32. The bracket, however, is grounded to the head of the machine by means of screws 44- which secure said bracket thereto. The circuit to the stop-motion mechanism is closed in this form of the invention when contact member 34 is grounded.

Secured to the front of the contact member is an insulating pad 49 which may be made of fiber or any other suitable material which is electrically non-conductive. It may be riveted to contact member 34 or secured thereto in any other suitable manner. It will be noted that a transverse groove 46 is formed across the lower end of insulating pad 4% and that the pad tapers below said groove to a fine edge. The tapered portion of the fiber pad below said groove is identified in the drawing by means of the reference character 43. It will be noted that this tapered portion does not project to the very bottom edge of contact member 34 but, rather, is spaced a predetermined distance above said bottom edge of the contact member.

Pivotally mounted arm 36 may simply be a Wire fixed intermediate its ends in a block This block is pivotally supported on a horizontal pin 52 which is supported on a pair of blocks or lugs 54 fixed to or integral with the horizontal portion 32b of bracket 32. These supporting members 54 may be struck up from the sides of said horizontal portion 32b of the bracket or they may be secured thereto or die-cast therewith or in any other suitable manner provided thereon.

The forward end of wire arm 36 may be bent over substantially at right angles to form a transversely extending probe portion it is this probe which projects into the space between the presser foot and the needle for engagement with the angular portion of the needle thread which forms when the bobbin thread breaks or terminates. The opposite or rear end of wire arm 36 may also be bent over to form a transverse portion 58 which serves as a contact member relative to contact member 34.

When the bobbin thread is whole and the needle thread is without its inclined portion, pivotally mounted wire arm 36 is maintained in cocked position by engagement of its bent end portion 58 with groove 46 in insulating pad 40. When the bobbin thread breaks or terminates, the needle thread will assume its angular position above mentioned and it will engage probe portion 56 of said pivoted arm 36. The pivoted arm will thereby be caused to turn in counter-clockwise direction as viewed in Fig. l and its bent end portion 58 will disengage the groove in the insulating pad 40 and it will move down tapered portion 48 of said pad and into engagement with the lower end of contact member 34. Since wire arm 36 is grounded through its supporting block 50 and pin 52 and blocks or lugs 54 on bracket 32 and since the bracket is itself grounded as has above been indicated to the head of the machine, the circuit to the stop-motion mechanism will now be closed.

To facilitate movement of bent end portion 58 of pivoted arm 36 into and out of engagement with groove 46 and into and out of engagement with the lower end of contact member 34, a roller 6%) may be mounted on said bent end portion 58. This would give said bent end portion a rolling movement into and out of said groove 46. Engagement of said roller with the lower end of contact member 34 would be in the nature of a wiping motion which would insure good electrical contact be tween said roller and said contact member and it would also insure against an accumulation of foreign matter on said contact member, and also on said roller, which might interfere with the transmission of electrical energy from one to the other of said elements.

Although the electrical circuit and the stop-motion mechanism to which reference has above been made are not shown in the drawing, it will be understood that one end of the stop-motion mechanism is grounded and the other end is connected to terminal 42 by means of a suitable conductor. This is a conventional electrical hookup and is not herein claimed. Any other suitable electrical hook-up between the switch and the stop-motion mechanism may be employed in this invention.

Turning now to the second form of this invention, it will be observed that sewing machine 70 is also a conventional machine and that it is provided with a presser foot 72 and a needle 74, the presser foot having an elongated needle opening 76 formed therein and an inclined groove or channel 78 formed in the heel of said presser foot and communicating with said elongated opening 76. Stop-motion switch 80 is made in accordance with the second form of this invention. It comprises the following elements: a supporting bracket 82 which may be secured to the back of the head of the machine by means of screws 84, a casing 86 on said bracket for enclosing and protecting the inner working parts of the switch, said casing being secured to the bracket by means of bolts 88 or any other suitable means, a pair of cars or lugs 90 formed or attached at the crook of said bracket, a pin 92 journaled into said ears or lugs 90, a probe 94 secured to said pin 92 and projecting forwardly therefrom (rightwardly as viewed in Fig. 3) a second arm 96 to pin 92 on the opposite side thereof, that is, projecting rearwardly therefrom, a second pair of ears or lugs 98 secured to or formed on said bracket a spaced distance above ears or lugs 90, a pin 100 supported by said ears 98, a bar 192 pivotally supported on pin 106 and movable into and out of engagement with the end of arm 96, a shoulder 104 on said bar to serve as a catch or stop relative to arm 96 in order to prevent accidental disengagement of said arm 96 from said bar 102, a spring type of contact member 196 secured to said bracket and positioned for engagement with bar 102 When the bar is in one position and for disengagement with said bar when the bar is in another position, a wire 108 projecting through a hole in the bracket and being pivotally engaged with said bar 102, and a knob 110 on the outer end of said wire for moving said wire and thereby controlling the position of bar 102.

The operation of switch 80 is basically similar to that of switch 30. When the bobbin thread breaks or terminates, needle thread 112 will assume its angular position through elongated opening 76 and inclined groove 78 of the presser foot. The needle thread will thereupon engage the transverse portion 94a of probe 94 and said probe will be tilted in counter-clockwise direction as viewed in Fig. 3. Since the probe is fixed to pin 92 and since arm 96 is also fixed to pin 92, this angular movement of the probe will be reflected in a downward counter-clockwise movement of said arm 96. The arm will thereupon disengage bar 102 and it will be noted from the angular position of said bar while engaged by arm 96 that said bar will pivot in counter-clockwise direction in response to the pull of gravity thereon immediately upon its release by arm 96. It may be found desirable to apply a weight 114 to bar 102 in order to facilitate its pivotal movement upon its release by arm 96.

When bar 102 thus pivots in counter-clockwise direction, its upper end will engage resilient contact member 106 and the circuit to the stop-motion mechanism will thereby be closed. Contact member 106 is insulated from bracket 82 but said bracket is grounded to the sewing machine head. Bolt 116 is the means of supporting contact member 106 on bracket 82 and it is also, of course, insulated from said bracket. Bolt 116 also serves as a binding post or terminal for a suitable conductor which is also connected to the stop-motion mechanism.

When it is desired to re-set switch 80, all that need be done is to push button or knob 110 leftwardly as viewed in Fig. 3. Since this button or knob is connected to a wire 108 which is also connected to bar 102, this leftward movement of the knob or button 110 will have the effect of thrusting the lower end of bar 102 leftwardly in clockwise direction. Bar 102 will now cam arm 96 downwardly in counter-clockwise direction until the lower end of said bar clears the arm. Arm 96 will now tend to swing upwardly in clockwise direction under the influence of the weight of probe 94 and particularly its bent end 9412. This clockwise movement of arm 96 will terminate upon the engagement of said arm with shoulder 104 of arm 102. The switch will now be set.

The foregoing illustrates preferred forms of this invention. It will be understood that these preferred forms may be modified and other forms may be provided and had Within the broad spirit of the invention and the broad scope of the claims.

I claim:

1. A stop-motion switch relating to sewing machine bobbin thread, comprising a bracket which is adapted to be secured to a sewing machine adjacent the presser foot and needle of said sewing machine, a pivotally mounted probe on said bracket which is adapted to project between the presser foot and needle of said machine for engagement with the needle thread of said machine when the bobbin thread breaks, an arm connected to said pivotally mounted probe and movable integrally therewith, a biased catch movably mounted on said bracket and engageable with said arm when the arm and probe occupy a given position in order to lock said arm and probe in said position, the catch being thereby itself locked in position and prevented from engaging in biased movement, said probe being adapted to be tripped by the needle thread when the bobbin thread breaks, thereby disengaging the arm from the catch and freeing the catch for biased movement, and means connected to said catch for closing a circuit when the probe is tripped by the needle thread and the catch is freed for biased movement, wherein the catch comprises a grooved pad of insulating material and the means which is connected to said catch for closing a circuit is a biased contact member, said insulated pad being mounted on said biased contact member and being biased therewith, the groove in said insulated pad being engageable with said arm to lock the arm and probe in their given position, said arm being itself a contact member and being engageable with the biased contact member to close the circuit when the probe is tripped and said arm is thereby dislodged from the groove in said insulated pad.

2. A stop-motion switch relating to sewing machine bobbin thread, comprising a bracket which is adapted to be secured to a sewing machine adjacent the presser foot and needle of said sewing machine, a pivotally mounted probe on said bracket which is adapted to project between the presser foot and needle of said machine for engagement with the needle thread of said machine when the bobbin thread breaks, an arm connected to said pivotally mounted probe and movable integrally therewith, a biased catch movably mounted on said bracket and engageable with said arm when the arm and probe occupy a given position in order to lock said arm and probe in said position, the catch being thereby itself locked in position and prevented from engaging in biased movement, said probe being adapted to be tripped by the needle thread when the bobbin thread breaks, thereby disengaging the arm from the catch and freeing the catch for biased movement, and means connected to said catch for closing a circuit when the probe is tripped by the needle thread and the catch is freed for biased movement, wherein the catch is itself a contact member and the means which is connected to said catch for closing a circuit is a second contact member mounted on the bracket, said catch being pivotally mounted on said bracket and being engageable, when in unbalanced position, with said arm to lock the arm and the probe in their given position, said catch being adapted to gravitate to a second position where it is engageable with the second contact member to close the circuit when the probe is tripped and the arm is thereby disengaged from said catch, a push-rod being provided On said bracket for longitudinal movement in both directions, one end of said push-rod being connected to the catch and a button being connected to the opposite end of said push-rod, whereby pushing said button causes said rod to move longitudinally of itself in one direction to swing the catch out of engagement with the second contact member and into engagement with the arm to lock said arm and the probe in their given position and also to lock said catch against gravitational movement into engagement with said second contact member.

References Cited in the file of this patent UNITED STATES PATENTS 1,455,387 Cobb May 15, 1923 2,387,369 Vossen Oct. 23, 1945 2,387,958 Vossen Oct. 30, 1945 2,410,718 Crawford Nov. 5, 1946 2,643,305 Mansson June 23, 1953 

